Building block



FIG. 1 is a front and side perspective view of a building block showingour new design;

FIG. 2 is a bottom and side perspective view of the first embodimentthereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a left side elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

CLAIM The ornamental design for a building block, as shown anddescribed.